Quantifying Agglomerate-to-Wall Impaction in Dry Powder Inhalers

Area of Science:

• Pharmaceutical Sciences
• Chemical Engineering
• Materials Science

Background:

• Understanding particle behavior in inhalation devices is crucial for effective drug delivery.
• Powder dispersion devices aim to deagglomerate particles for optimal aerosolization.
• Agglomerate-to-wall collisions influence the efficiency of powder dispersion.

Purpose of the Study:

• To quantify the probability of agglomerate-to-wall collisions using advanced imaging techniques.
• To investigate the impact of flow rate and particle size on colliding agglomerates.
• To develop a predictive model for agglomerate-wall collisions in dispersion devices.

Main Methods:

• Utilized high-speed microscopic imaging and unique image processing to analyze collision events.
• Employed an in-house powder dispersion device with variable configurations, mimicking commercial inhalers.
• Tested various powder samples, including carrier Respitose® SV010 and mannitol particles of different sizes, at flow rates of 30 and 60 SLPM.

Main Results:

• Collision frequencies varied significantly with constituent particle size at 30 SLPM, but this effect diminished at 60 SLPM.
• Increasing flow rate to 60 SLPM led to a significant rise in the proportion of colliding particles for all tested powders.
• Agglomerate diameter and velocity were found to positively correlate with the probability of collision.

Conclusions:

• The probability of agglomerate-to-wall collision is influenced by particle characteristics and flow dynamics.
• A logistic regression model was successfully developed, accurately predicting collisions across different powders and flow rates.
• This research provides valuable insights for optimizing powder dispersion device design and performance.